Mozilla has a service that promises a layer of anonymity from marketing firms that may sell your email. Well, I've tried it numerous times and it is a rejected domain. So, don't waste your time. I don't think this will improve because Mozilla doesn't engage feedback from users, has obtuse and stale "support" options. Apparently they rely on guidance from a insular club of selected "experts". This is typical for software companies, the neophyte public is incidental to their operation and really prefer to service their rewarded cheering section.